1. Field of the Invention
The present invention relates to a numerical control system, and particularly relates to a numerical control system that enables a position of an input/output (I/O) unit at which a defect occurs to be easily detected.
2. Description of the Related Art
A configuration, in which a plurality of external signal input/output units (I/O units) is connected, has been employed to input and output a digital input/digital output (DI/DO) signal (input signal/output signal) between a numerical controller and a machine tool. Normally, DI/DO data (input data/output data) is exchanged between a numerical controller and an I/O unit. In such a configuration, when a defect such as cable disconnection between I/O units or instantaneous interruption of power supply of an I/O unit is detected, for example, a conventional art such as JP 4291384 B2 is publicly known as a method of discriminating a cause of the defect and a place in which the defect occurs.
In general, I/O units are mounted inside a control panel of a machine tool such that each of the I/O units is dispersed. In addition to the I/O units, a terminal block corresponding to input/output destinations of the I/O units, a relay, an electromagnetic switch, a sensor, etc. are mounted inside the control panel. In addition, a power supply, a servo amplifier, and a controller of the numerical controller may be mounted. With regard to wiring of a cable that connects these devices to each other, it is desirable that each group of devices corresponding to cables having close electric potentials be combined and separated from another group in consideration of a measure against noise. Since the above-described design constraints are present, a computer aided design (CAD) for mechanical design and electric design is used in some cases to support mounting and disposition of various devices inside the control panel or design of wiring between devices in the design and manufacture of the control panel (for example, JP 07-152797 A, JP 5113676 B2, JP 10-040276 A, JP 06-282609 A, etc.).
However, a fault detecting function disclosed in JP 4291384 B2 can accurately discriminate a cause and a location of a fault in a case in which a defect such as cable disconnection between I/O units or instantaneous interruption of power supply of an I/O unit is detected. Since various devices are mounted and disposed inside a control panel, an actual location of a fault inside the control panel may not be specified when a mounting diagram or a circuit diagram is not checked.
In addition, an application for displaying disposition of various devices inside a control panel on a screen may be prepared to visually display a location of a fault. In this case, a screen corresponding to disposition inside the control panel which is different among individual machines may need to be prepared, and introduction thereof is time-consuming.